A group is a window that draws a bordered line all around.
This makes it draw a limiting placeholder for other controls. To indicate what
it is used for, a group box may display a title, also referred to as its
caption. Here is an example of a group box on a form:

Group Box Creation

To support group box, the .NET Framework provides the GroupBox
class. At design time, to add a group box to your application, from the
Containers section of the Toolbox, click GroupBox and click the form (or another
container). To programmatically create a group box, you can create a handle to GroupBox,
allocate memory for it using the new operator, and add it to the
Controls collection of its container. Here is an example:

As you can see from the above picture, a group may or may
not display a caption. If you need to display a caption on it, at design time,
in the Properties window, click Text and type a string. To do this
programmatically, assign a string to the Text property of the group box control.
Here is an example:

Besides serving a delimiter of an area on a form, a group
box can also serve as a container. That is, a group box can carry or hold other
containers. As such, you can create a control and add it to its collection of
controls. When you add a control to a group box, whether at design or run time,
the location you specify is relative to the group box and not to the form.
Because the group box will act as the parent, it is its client area that is
considered for the location of its child(ren) control(s).

Since a group box can serve as a control container, at
design time (and at run time), you can add the desired controls to it. Here is
an example:

Notice that it is possible to have a control whose size
causes some of its section to be hidden. To accommodate the control(s)
positioned in a group box, you can make the container resize itself so as to
reveal the hidden part(s) of its controls. To support this, the GroupBox
class is equipped with the Boolean AutoSize property. The default value
of the GroupBox.AutoSize property is false. If you set it to true, the
group box would resize itself and all of its controls should appear:

Giving Focus to a Group Box

If you are done programming in Win32, you would know that
the Microsoft Windows operating system classifies the group box as a static
controls. One of characteristics of static controls is that they cannot receive
focus. In other words, you cannot actually click a group box and it cannot
indicate that it has received focus. At the same time, in the .NET Framework,
the GroupBox class is equipped with the TabStop and the TabIndex
properties, which suggests that, by pressing Tab while using a form that has a
group box, the group box should receive focus at one time. Still, because the
group box is a static control, it cannot receive focus. What actually happens is
that, whenever a group box is supposed to receive, it transfers the focus to its
first or only control.

Using a Mnemonic

As mentioned already, a group box can be equipped with a
caption, which is created by assigning a string to its Text property. A mnemonic
is a character (or a letter) that the user can use to access a group box. To
create a mnemonic, precede one character (or one letter) of its caption with
&. Here is an example:

Using the mnemonic, the user can press Alt and the
underlined character to give focus to a control inside the group box.